The invention relates to the field of anti-pathogen device, methods of making anti-pathogen devices and uses of anti-pathogen devices, particularly for use with viruses and bacteria.
The use of sialic acid and its derivatives is generally known for capturing viruses. Sialic acid is a generic term used for a family of 9-carbon monosaccharides structurally deduced from neuraminic acid. Currently more than 50 different sialic acids have been found in nature with a variety of structures. They are widely found in higher animals and to a lesser extent in other species ranging from plants and fungi to yeasts and bacteria. In humans, sialic acids are mainly derived from Neu5Ac (N-Acetyl neuraminic acid) and usually occur as terminal units on cell-surface conjugates. Due to the occurrence as terminal molecules on cell-surfaces, sialic acids take part in a variety of complex and important physiological and pathological events including cellular and molecular recognition processes. Sialic acid also plays an important role in viral and bacterial infections.
Many viruses use sialic acid to enable them to recognise and bind to their target host cell membranes. The human influenza virus (Orthomyxoviridae), for example, has hemagglutinin (HA) protein on the virion protein coat or protruding through the envelope. The role of HA during viral entry into a host's cells is to bind to sialic acid receptors found on the cell membranes of human erythrocytes and the upper respiratory tract. Once the virus is bound to the cell membrane, a hole forms in the cell membrane and the virus particle and/or its genetic contents are released into the host cell, where viral reproduction begins. Similar mechanisms occur with viruses such as BK virus, adenovirus type 37, malaria, herpes simplex. HIV, cholera, sindbis, tumours, hepatitis, coxsackievirus A24 variant, rotavirus strains, and new and old world arenavirus (including ebola and rabies).
On the other hand, many other pathogens have evolved to decorate their own cell surfaces with sialic acid. Bacterium, in particular, incorporate sialic acid into their own cell surface features, although this characteristic is usually limited to those that live in association with higher animals (deuterostomes). The sialic acid-decorated cell surfaces of a bacterium enable them to disguise themselves and resist a host's innate immune response.
In order to defend against viral and bacterial infections, it is advantageous to be able to neutralise them or remove their infectious capability.
In view of the role that sialic acid plays in the infection pathway of both bacteria and viruses, it is considered helpful in the process of neutralisation or removal of their infectious capability. It is also thought that the combination of sialic acid with other components, such as a carrier with absorbance characteristics, or other anti-viral and/or anti-bacterial factors that could cause viral or bacterial death, might be advantageous.
However, sialic acid and its derivatives are not readily attached to other such carriers or factors. For example, there are a variety of other known components that are known for their anti-pathogen device and pathogen fighting abilities. One of these components is activated carbon and WO2011/062996 discloses an adaptable component having anti-pathogen device and virucidal properties, comprising a metal impregnated activated carbon cloth, an inner layer positioned along one side of the cloth and an outer layer positioned along the opposite side of the cloth. The layers can be attached together along all or a portion of a perimeter. The metal used is at least one of copper and silver, which are known as antimicrobials.
In addition, sialic acids are often ‘weak’ ligands for pathogens when they are ‘free’ (unbound). This has been observed between ‘free’ sialic acid and the HA protein.
It has therefore been an aim of the present invention to provide an improved anti-pathogen device using sialic acid.